Noble gases and nitrogen in samples of asteroid Ryugu record its volatile sources and recent surface evolution.
Ryuji OkazakiBernard MartyHenner BusemannKo HashizumeJamie D GilmourAlex MeshikToru YadaFumio KitajimaMichael W BroadleyDavid J ByrneEvelyn FüriMy E I RiebeDaniela KrietschColin MadenAkizumi IshidaPatricia ClaySarah A CrowtherLydia FawcettThomas LawtonOlga PravdivtsevaYayoi N MiuraJisun ParkKen-Ichi BajoYoshinori TakanoKeita YamadaShinsuke KawagucciYohei MatsuiMizuki YamamotoKevin RighterSaburo SakaiNaoyoshi IwataNaoki ShiraiShun SekimotoMakoto InagakiMitsuru EbiharaReika YokochiKunihiko NishiizumiKeisuke NagaoJong Ik LeeAkihiro KanoMarc W CaffeeRyu UemuraTomoki NakamuraHiroshi NaraokaTakaaki NoguchiHikaru YabutaHisayoshi YurimotoShogo TachibanaHirotaka SawadaKanako SakamotoMasanao AbeMasahiko ArakawaAtsushi FujiiMasahiko HayakawaNaoyuki HirataNaru HirataRie HondaChikatoshi HondaSatoshi HosodaYu-Ichi IijimaHitoshi IkedaMasateru IshiguroYoshiaki IshiharaTakahiro IwataKosuke KawaharaShota KikuchiKohei KitazatoKoji MatsumotoMoe MatsuokaTatsuhiro MichikamiYuya MimasuAkira MiuraTomokatsu MorotaSatoru NakazawaNoriyuki NamikiHirotomo NodaRina NoguchiNaoko OgawaKazunori OgawaTatsuaki OkadaChisato OkamotoGo OnoMasanobu OzakiTakanao SaikiNaoya SakataniHiroki SenshuYuri ShimakiKei ShiraiSeiji SugitaYuto TakeiHiroshi TakeuchiSatoshi TanakaEri TatsumiFuyuto TeruiRyudo TsukizakiKoji WadaManabu YamadaTetsuya YamadaYukio YamamotoHajime YanoYasuhiro YokotaKeisuke YoshiharaMakoto YoshikawaKento YoshikawaShizuho FuruyaKentaro HatakedaTasuku HayashiYuya HitomiKazuya KumagaiAkiko MiyazakiAiko NakatoMasahiro NishimuraHiromichi SoejimaAyako I SuzukiDaiki YamamotoKasumi YogataMiwa YoshitakeRyohta FukaiTomohiro UsuiHarold C ConnollyDante S LaurettaSei'ichiro WatanabeYuichi TsudaPublished in: Science (New York, N.Y.) (2022)
The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measure noble gas and nitrogen isotopes in Ryugu samples, finding they are dominated by pre-solar and primordial components, incorporated during Solar System formation. Noble gas concentrations are higher than those in Ivuna-type carbonaceous (CI) chondrite meteorites. Several host phases of isotopically distinct nitrogen have heterogeneous abundances between the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating ~5 Myr exposure, and from implanted solar wind, record the recent irradiation history of Ryugu after it migrated to its current orbit.